Dense Wavelength Division Multiplexing (DWDM) technology greatly expands networks' capacity over existing network infrastructures by the simultaneous transmission of hundreds of wavelengths over a single fiber. DWDM transmission has been widely deployed in long haul service provider networks, and is increasingly being deployed in metro service provider networks and for enterprise data center connectivity applications. While DWDM is universally used in transmission, different switching technologies can be used to direct input data to outputs at router nodes. Current switching technologies fall into either electronic switching or optical switching technologies, based on how data is processed in the router. Electronic switching technology, also known as electronic packet switching (EPS), converts DWDM optical signals to electronic signals, and processes data (usually in the form of packets) electronically. However, as the number of DWDM channels increases, the optical/electrical/optical (O/E/O) conversion required by electronic switching significantly adds cost to the overall system cost. For example, while it is technologically feasible to carry 512 wavelengths in a single optical fiber, it requires 512 O/E/O pairs in EPS routers to just terminate a single DWDM link. Optical switching technologies, on the other hand, allow DWDM channels to pass the router node optically, which greatly reduces the cost of deploying DWDM channels over existing network infrastructure. Optical switching can be further divided into three technologies: Optical Circuit Switching (OCS), Optical Packet Switching (OPS), and Optical Burst Switching (OBS). Unfortunately, there is no single switching technology that can cost-effectively scale with the number of DWDM channels while meeting the diverse needs of heterogeneous applications.
From the application's perspective, Internet traffic is inherently heterogeneous, embracing all data generated by applications that differ greatly in nature (e.g., VoIP, Video-on-Demand (VoD), IPTV, 3G/WiMax, Virtual-Private-Network (VPN), 10 Gigabit Ethernet). No single switching technology (EPS, OCS or OBS) appears to be suitable for a variety of different applications. Although optical switching technologies have advantages in scaling up DWDM systems, neither OCS nor OBS can switch at the packet level. For example, applications transporting short, latency sensitive messages desires fine packet level granularity. Even between the two optical switching technologies, OCS and OBS, it is hard to declare a winner for all types of applications. While it is clear that OBS performs well for most of bursty Internet traffic, OCS is more suitable for applications that require sustained, long-term full channel bandwidth (i.e. 10 Gb/s and above). OCS is also a better fit for mission critical applications which cannot tolerate any data loss or variable delay. One can conceivably build separate networks using different switching technologies to meet respective needs of applications. However, for some applications, this implies a higher capital investment, more management issues, and less flexibility. Unfortunately, there is no single type of network that can best fit the need for different applications due to the varying characteristics of different types of messages within the application. Although attempts have been made to support specific applications in the network, none of them address the DWDM channel scaling issue.
The DWDM multi-mode switching methods and apparatuses discussed herein overcomes the above-mentioned limitations by supporting multiple switching technologies (EPS, OBS and OCS) in DWDM-based communication networks. The methods and apparatuses discussed provide for dynamically configuring and reconfiguring multi-mode switching routers.